game card updates are often incomplete hence all the advice to use sysupdater you can currently hack your 3ds using this guide [Tutorial] Installing rxTools Custom Firmware - (3DS and 2DS) (sysupdater instructions in the guide as well )
but if you really want to do it via game card update then use this website 3DS Releases to find a game that needs 9.2 and buy it
btw i advise you go with sysupdater